The invention concerns a hot and cold engine, operating based on a regenerative gas cyclical process, and having at least two pistons that separate at least three processing chambers with respectively at least one in-line arranged heat exchanger and at least one regenerator arranged in series with the heat exchanger.
Hot and cold engines that operate based on a regenerative gas cyclical process, for example based on the Stirling or Vuilleumier cyclical process, have been known for a long time, e.g. from the GP-PS 136 195. Such engines have two pistons that move linearly inside a pressure-sealed housing and jointly delimit a warm working volume. One of these pistons delimits a hot working volume admitted with heat inside the housing and the other piston delimits a cold working volume, wherein the three working volumes are connected to each other, with an in-line arrangement of regenerators and heat exchangers, and wherein a drive and/or a control for the pistons is provided.
Despite the undisputable advantages of the hot and cold engines operating based on a regenerative gas cyclical process, these engines have not been used in practical operations so far, primarily because of design problems, which have so far prevented the realization of the theoretical advantages of such engines in practical operations.
With hot and cold engines operating based on a regenerative gas cyclical process, which are used for the heating and cooling of buildings and vehicles and are provided with a heat exchanger functioning as heat source that is admitted by environmental air, there is the danger that the air heat exchanger freezes at air temperatures around the freezing point and high humidity levels. In that case, the cold heat exchanger of the engine also freezes because of the continued engine operation. This danger of freezing exists even if interruptions occur in the cold cycle of the engine, e.g. if the circulating pump fails.
In order to eliminate this danger, it is known to thaw out the air heat exchanger or to heat it before it freezes. This requires expensive heating devices, which are not only very undesirable, but also require extensive controls that normally also result in a shutting down of the complete engine.
It is the object of the invention to create a hot and cold engine operating based on a regenerative gas cyclical process, for which the freezing danger for the cold heat exchanger is removed in an energy-efficient way with simple design means and simple regulation technology.